Disagreements that resist rational resolution, often termed “deep disagreements”, have been the focus of much work in epistemology and informal logic. In this paper, I argue that they also deserve the attention of philosophers of mathematics. I link the question of whether there can be deep disagreements in mathematics to a more familiar debate over whether there can be revolutions in mathematics. I propose an affirmative answer to both questions, using the controversy over Shinichi Mochizuki’s work on the abc conjecture (...) as a potential example of both phenomena. I conclude by investigating the prospects for the resolution of mathematical deep disagreements in virtue-theoretic approaches to informal logic and mathematical practice. (shrink)

The fallacy fallacy is either the misdiagnosis of fallacy or the supposition that the conclusion of a fallacy must be a falsehood. This paper explores the relevance of these and related errors of reasoning for the appraisal of arguments, especially within virtue theories of argumentation. In particular, the fallacy fallacy exemplifies the Owl of Minerva problem, whereby tools devised to understand a norm make possible new ways of violating the norm. Fallacies are such tools and so are vices. Hence a (...) similar problem arises with argumentative vices. Fortunately, both instances of the problem have a common remedy. (shrink)

The analysis of multimodal argumentation in advertising is a crucial and problematic area of research. While its importance is growing in a time characterized by images and pictorial messages, the methods used for interpreting and reconstructing the structure of arguments expressed through verbal and visual means capture only isolated dimensions of this complex phenomenon. This paper intends to propose and illustrate a methodology for the reconstruction and analysis of “double-mode” arguments in advertisements, combining the instruments developed in social semiotics, pragmatics, (...) and argumentation theory. An advertisement is processed through a five-step path. The analysis of its context, text genre, and images leads to a first representation of the messages that it encodes both pictorially and verbally (step 1). These first semantic representations are further enriched by including their polyphonic articulations and presuppositions (step 2), their explicatures (step 3), and their dialogical functions and illocutionary forces (step 4). These pragmatic steps retrieve the commitment structure of the ad, which allows a further argument analysis conducted through argumentation schemes (step 5). (shrink)

Formal logic has often been seen as uniquely placed to analyze mathematical argumentation. While formal logic is certainly necessary for a complete understanding of mathematical practice, it is not sufficient. Important aspects of mathematical reasoning closely resemble patterns of reasoning in nonmathematical domains. Hence the tools developed to understand informal reasoning, collectively known as argumentation theory, are also applicable to much mathematical argumentation. This chapter investigates some of the details of that application. Consideration is given to the many contrasting meanings (...) of the word “argument”; to some of the specific argumentation-theoretic tools that have been applied to mathematics, notably Toulmin layouts and argumentation schemes; to some of the different ways that argumentation is implicated in mathematical practices; and to the social aspects of mathematical argumentation. (shrink)

In this paper, we use concepts, structure and tools from argumentation theory to show how conversational implicatures are triggered by conflicts of presumptions. Presumptive implicatures are shown to be based on defeasible forms of inference used in conditions of lack of knowledge, including analogical reasoning, inference to the best explanation, practical reasoning, appeal to pity, and argument from cause. Such inferences are modelled as communicative strategies to knowledge gaps that shift the burden of providing the missing contrary evidence to the (...) other party in a dialogue. Through a series of illustrative examples, we show how such principles of inference are based on common knowledge about the ordinary course of events shared by participants in a structured dialogue setting in which they take turns putting forward and responding to speech acts. (shrink)

semantic minimalism and moderte contextualism.

An introduction to philosophy of language since Frege, focusing on the 20th century.

Walter Sinnott-Armstrong argues that moral disagreement and widespread moral bias pose a serious problem for moral intuitionism. Seneca’s view that we just recognise the good could be criticised using a similar argument. His approach to argumentation offers a way out, one that may serve as a model for a revisionary intuitionism.

Pragmatic presuppositions are analyzed considering their relation with the notion of commitment, namely the dialogical acceptance of a proposition by an interlocutor. The attribution of commitments carried out by means of pragmatic presupposition is shown to depend on the reasonableness of the underlying presumptive reasoning, ultimately grounded on hierarchies of presumptions. On this perspective, the ordinary interpretation of pragmatic presuppositions as the “taking for granted” of propositions signaled by semantic or syntactic triggers becomes only the presumptive, prototypical interpretation of a (...) complex linguistic and pragmatic phenomenon. It will be shown how the prototypical interpretation is subject to default in cases of conflicts of presumptions, which lead to reconstructing the speaker’s meaning non-presumptively at a pragmatic, semantic, or syntactic level. The phenomena of presupposition cancellation and neutralization can be explained in terms of presumptive and non-presumptive articulation and interpretation of an utterance, through which the speaker can impose, correct, or refuse implicit commitments. (shrink)

Our main aim is to discuss the topic of scientific controversies in the context of a recent issue that has been the centre of attention of many epistemologists though not of argumentation theorists or philosophers of science, namely the ethics of belief in face of rational disagreement. We think that the consideration of scientific examples may be of help in the epistemological debate on rational disagreement, making clear some of the deficiencies of the discussion as it has been produced until (...) now. Another central claim of our paper is that the common view according to which beliefs (and changes of beliefs) may exhibit and commonly exhibit a deontic status can be clarified in the light of Brandom’s approach to normative pragmatics and the pragmatic theories of argumentation that also have a normative character (here our example is van Eemeren’s pragma-dialectics). Our article highlights the similarities between both projects, similarities that to our knowledge were not noticed before. Finally, an important point of the article is that we need to take contextual elements into account in order to develop an adequate theory of disagreement. (shrink)

A persuasion dialogue is a dialogue in which a conflict between agents with respect to their points of view arises at the beginning of the talk and the agents have the shared, global goal of resolving the conflict and at least one agent has the persuasive aim to convince the other party to accept an opposing point of view. I argue that the persuasive force of argument may have not only extreme values but also intermediate strength. That is, I wish (...) to introduce two additional types of the effects of persuasion in addition to successful and unsuccessful ones (cf. Van Eemeren and Houtlosser in Argumentation 14(3):293–305, 2000; Advances in pragma-dialectics. Sic Sat, Amsterdam, 2002; Walton in A pragmatic theory of fallacy. University of Alabama Press, Tuscaloosa, 1995; Walton and Krabbe in Commitment in dialogue: basic concepts of interpersonal reasoning. State University of New York Press, Albany, New York, 1995). I propose a model which provides for modified versions of the standpoint of an agent needed in order to bring about two possible outcomes of a persuasion dialogue. These two outcomes I label partially-successful and over-successful. I call the potential, not yet verbalised, standpoint of an agent here the original topic t. Based on some aspects of relevance theory (Sperber and Wilson in Relevance: communication and cognition. Blackwell, Oxford, 1986; Wilson and Sperber in The handbook of pragmatics. Blackwell Publishing, Malden, 2006), I explain that the modified version of the original topic t is an implicature created from the original topic t and from a specific mental topic which belongs to, what I call the beneficial cognitive model (hence BCM). I define BCMi,t as a set of topics which are within the area of agent i’s interest of persuasion with respect to t. (shrink)

lt is now commonplace in fallacy inquiry for many of the traditional informal fallacies to be viewed as reasonable or nonfallacious modes of argument. Central to this evaluative shift has been the attempt to examine traditional fallacies within their wider contexts of use. However, this pragmatic turn in fallacy evaluation is still in its infancy. The true potential of a contextual approach in the evaluation of the fallacies is yet to be explored. I examine how, in the context of scientific (...) inquiry, certain traditional fallacies function by conferring epistemic gains upon inquiry. Specifically, I argue that these fallacies facilitate the progression of inquiry, particularly in the initial stages ofinquiry when the epistemic context is one of uncertainty. The conception of these fallacies that emerges is that of heuristics of reasoning in contexts of epistemic uncertainty. (shrink)

What type of speech act is a norm of action, when the norm is agreed upon as the conclusion of an argumentative dialogue? My hypothesis is that, whenever a norm of action is the conclusion of an argument, it should be analyzed as the statement of a norm and thus as a verdictive speech act. If the context is appropriate, and the interlocutors are sincerely (or institutionally) committed to their argumentative exchange and its conclusion, then this verdictive motivates and institutes (...) a new one with the force of an exercitive. The interlocutors’ recognition and acceptance that the new illocution has been performed lends the norm its exercitive force. (shrink)

Technology has made argumentation rampant. We can argue whenever we want. With social media venues for every interest, we can also argue about whatever we want. To some extent, we can select our opponents and audiences to argue with whomever we want. And we can argue however we want, whether in carefully reasoned, article-length expositions, real-time exchanges, or 140-character polemics. The concepts of arguing, arguing well, and even being an arguer have evolved with this new multiplicity and diversity; theory needs (...) to catch up to the new reality. Successful strategies for traditional contexts may be counterproductive in new ones; classical argumentative virtues may be liabilities in new situations. There are new complications to the theorist’s standard questions—What is an argument? and Who is an arguer?—while new ones move into the spotlight—Should we argue at all? and If so, why? Agent-based virtue argumentation theory provides a unifying framework for this radical plurality by coordinated redefinitions of the concepts of good arguers and good arguments. It remains true that good arguers contribute to good arguments, and good arguments satisfy good arguers, but the new diversity strains the old unity. Ironically, a unifying factor is provided by examining those paragons of bad arguers, argument trolls whose contributions to arguments are not very good, not really contributions, and, ultimately, not genuine argumentation. (shrink)

In this article we present a training program based on the empirical research conducted in the project 'argumentational integrity'. After a brief sketch of the problem dimensions concerning unfair argumentation we give an overview of the training concept and the underlying empirical research. Exemplification of the instructional design is given for the second and the fifth training dimension (standards of argumentational integrity and reactions to unfair contributions). Finally we indicate how the training is to be evaluated and present initial results (...) demonstrating that in comparison with an untrained control group participants in the training significantly improve their skills in identifying and naming argumentative rule violations. (shrink)

This article proposes a cost-benefit analysis of argumentation, with the aim of highlighting the strategic considerations that govern the agent's decision to argue or not. In spite of its paramount importance, the topic of argumentative decision-making has not received substantial attention in argumentation theories so far. We offer an explanation for this lack of consideration and propose a tripartite taxonomy and detailed description of the strategic reasons considered by arguers in their decision-making: benefits, costs, and dangers. We insist that the (...) implications of acknowledging the strategic dimension of arguing are far-reaching, including promising insights on how to develop better argumentation technologies. (shrink)

When parties attempt to persuade their opponents of the tenability of a certain standpoint using reasons, they will often find that the circumstances of the dialogue hinder their chances of resolution. Power imbalances, cognitive biases, lack of time or hidden interests are some of the circumstances they need to face. I will label these circumstances as _suboptimal settings for argumentation_. According to the pragma-dialectical tradition, higher-order conditions for critical discussion are unfulfilled in these cases (van Eemeren, Grootendorst, Jacobs, & Jackson, (...) 1993). The main question of this paper is the following: what is the normative standard that parties in a discussion need to follow to arrive at a resolution within such circumstances? I will defend a middle-ground solution between two extreme ones. The first extreme position, the _anything-goes policy_, claims that, given that the conditions for a reasonable exchange of reasons are not satisfied, the dialogue stands outside the domain of reason, so anything goes for the parties. The second extreme position, the _business as usual policy_, claims that, since critical discussion is a normative model, the same rules should apply in suboptimal settings. Finally, the _supernormal policy_ that I defend claims that we need a more general and comprehensive norm that I refer to as a _supernorm_ to evaluate these cases. The supernormal policy divides argumentation into two stages: preparation and resolution. In the preparation stage, the parties attempt to restore or compensate for the suboptimality of the setting, while in the resolution stage, they attempt to resolve their disagreement. I contend that the moves of the preparation stage should be evaluated by using the supernorm instead of by the rules for critical discussion (van Eemeren and Grootendorst 2004 ). At this point, the paper considers theoretical insights from Gilbert ( 1995, 1997, 2002 ) and Jacobs ( 2000, 2006 ) to understand what this entails. (shrink)

A broad assumption in argumentation theory is that argumentation primarily regards resolving, confronting, or managing disagreement. This assumption is so fundamental that even when there does not appear to be any real disagreement, the disagreement is suggested to be present at some other level. Some have questioned this assumption (most prominently, Perelman and Olbrechts-Tyteca, and Doury), but most are reluctant to give up on the key idea that persuasion, the core of argumentation theory, can only regard disagreements. We argue here (...) that this assumption is false. Argument may be as much about strengthening or maintaining agreement as it is about disagreement. Once we see how argument is possible and manifestly enacted under conditions of agreement, then we have tools to explain otherwise curious fallacies and argumentative phenomena. (shrink)

The concept of adversariality, like that of argument, admits of significant variation. As a consequence, I argue, the question of adversarial argument has not been well understood. After defining adversariality, I argue that if we take argument to be about beliefs, rather than commitments, then two considerations show that adversariality is an essential part of it. First, beliefs are not under our direct voluntary control. Second, beliefs are costly both for the psychological states they provoke and for the fact that (...) they are causally related to our actions. As a result, argument involving agreement can also be understood to be adversarial. (shrink)

Some disagreements seem to be persistent: they are, pretty much, immune to persuasive argumentation. If that is the case, how can they be overcome? Can argumentation help us? I propose that to overcome persistent disagreements through argumentation, we need a dynamic and pluralistic version of argumentation. Therefore, I propose that argumentation, more than a tool that uses persuasion to change the mind of the counterpart, is a toolbox that contains persuasion, deliberation, negotiation, and other dialogical strategies that can be used (...) to reach an agreement. (shrink)

In argumentation studies, almost all theoretical proposals are applied, in general, to the analysis and evaluation of argumentative products, but little attention has been paid to the creative process of arguing. Mathematics can be used as a clear example to illustrate some significant theoretical differences between mathematical practice and the products of it, to differentiate the distinct components of the arguments, and to emphasize the need to address the different types of argumentative discourse and argumentative situation in the practice. I (...) consider some issues of recent papers associated with mathematical argumentation in an attempt to contribute to the discussion about the role of arguing in mathematical practice and in the evaluation of the products of this practice. I apply this discussion to learning environments to defend the thesis that argumentative practice should be encouraged when teaching technical subjects to convey a better understanding and to improve thought and creativity. (shrink)

Over the last five decades, philosophers of language have looked into the mechanisms for doing things with words. The same attention has not been devoted to how to undo those things, once they have been done. This paper identifies and examines three strategies to make one’s speech acts undone—namely, Annulment, Retraction, and Amendment. In annulling an act, a speaker brings to light its fatal flaws. Annulment amounts to recognizing an act as null, whereas retraction and amendment amount to making it (...) null. Speakers employ retraction to cancel the deontic updates engendered by a given act. They instead use amendment to adjust its degree of strength. I will argue that annulling, retracting, and amending are second-order speech acts, whose felicity conditions vary with the type of illocution they operate on. Undoing is therefore conceived of as a form of doing. Furthermore, I claim that, in calling off our acts, we undo the conventional or illocutionary effects of our words while leaving intact their past causal or perlocutionary outcomes. (shrink)

Compliance is often achieved ‘by design’ through a coherent system of controls consisting of information systems and procedures. This system-based control requires a new approach to auditing in which companies must demonstrate to the regulator that they are ‘in control’. They must determine the relevance of a regulation for their business, justify which set of control measures they have taken to comply with it, and demonstrate that the control measures are operationally effective. In this paper we show how value-based argumentation (...) theory can be applied to the compliance domain. Corporate values motivate the selection of control measures (actions) which aim to fulfil control objectives, i.e. adopted norms (goals). In particular, we show how to formalize the audit dialogue in which companies justify their compliance decisions to regulators using value-based argumentation. The approach is illustrated by a case study of the safety and security measures adopted in the context of EU customs regulation. (shrink)

Building on our diverse research traditions in the study of reasoning, language and communication, the Polish School of Argumentation integrates various disciplines and institutions across Poland in which scholars are dedicated to understanding the phenomenon of the force of argument. Our primary goal is to craft a methodological programme and establish organisational infrastructure: this is the first key step in facilitating and fostering our research movement, which joins people with a common research focus, complementary skills and an enthusiasm to work (...) together. This statement—the Manifesto—lays the foundations for the research programme of the Polish School of Argumentation. (shrink)

Pragmatics and dialectics are two disciplines which have been amongst the first and most important partners for argument studies in the exploration of the complex realm of communication. Treating argumentation as a construct consisting of premises and conclusion allows for investigating some interesting properties of the phenomenon of reasoning, but does not capture a variety of aspects related to the usage of natural language and dialogical context in which real-life argumentation is typically embedded. This special issue explores some of the (...) fascinating research questions which emerge when we move beyond logic into the territory of the pragmatics and dialectics of argument. (shrink)

Ethotic arguments, such as arguments from expert opinion and ad hominem arguments, play an important role in communication practice. In this paper, we argue that there is another type of reasoning from ethos, in which people argue about actions in the world. These subspecies of ethotic arguments are very common in public debates: societies are involved in heated disputes about what should be done with monuments of historical figures such as Stalin or Colston: Should we demolish the building they funded? (...) Should we revere their statues? Should the street named after them be renamed?; and the general public vividly argue about what should be done with the legacy of producers, directors and actors in debates of the #MeToo movement: Should their new movies be distributed? Should their scenes be deleted from motion pictures? Should their stars from the Hollywood Walk of Fame be removed? Many arguments in these debates boil down to the character of the public figures: He was a slave trader!—But he is a part of our history; He harassed a young girl!—But he is an important actor. The reasoning step here is legitimised by the association between a person and an extra-linguistic object: the association between a historical figure and their statue or between an actor and their movie. The nature of this association is explained in the paper using Peirce’s theory of signs. We propose to extend an existing approach to patterns of reasoning from ethos that will help us to shed new light on ethotic argumentation and open an avenue for a systematic account of these unexplored argument forms. (shrink)

En el presente artículo utilizamos el concepto de filosofía formalizada de Hansson, así como las categorías de idealización simplificada y perfeccionista que se le asocian, con el fin de proponer un metaanálisis de tres enfoques teóricos de la argumentación, a saber, la pragmadialéctica de van Eemeren y Grootendorst, los esquemas argumentativos de Walton y el enfoque conversacional de Jacobs y Jackson, en relación con el tratamiento de las falacias como un tipo de trasgresión de reglas pragmáticas. Concluimos que mientras las (...) dos primeras están ancladas en una concepción centralizada de lo falaz, la tercera abandona toda posibilidad de normatividad. (shrink)

Gilbert (2000) examined the issue of collective intentionality in science. Her paper consisted of a conceptual analysis of the negative role of collective belief, consensus, and joint commitment in science, with a brief discussion of a case study investigated by Thagard (1998a, 1998b). I argue that Gilbert's concepts have to be refined to be empirically more relevant. Specifically, I distinguish between different kinds of joint commitments. I base my analysis on a close examination of Thagard's example, the discovery of Helicobacter (...) pylori, and two other historical cases involving the Copenhagen school of quantum mechanics and the Austrian school of economics. I also argue that it is difficult to fulfill the condition of common knowledge, even in Gilbert's weak sense. I conclude by raising serious doubts about the very possibility of a certain type of joint commitment, which I refer to as an implicit joint commitment. (shrink)

The issue of knowing what it means for a group to have collective beliefs is being discussed more and more in contemporary philosophy of the social sciences and philosophy of mind. Margaret Gilbert’s reconsideration of Durkheim’s viewpoint in the framework of the plural subject’s account is one of the most famous. This has implications in the history and the sociology of science—as well asin the history and sociology of philosophy—although Gilbert only outlined them in the former fields and said nothing (...) about the latter. Symmetrically but independently, a historian of science, Mara Beller, has recently challenged Kuhn’s conception of the role of consensus in sciences in a brilliant analysis by carefully studying the history of Copenhagen School of Quantum Mechanics. Not only does she show the role of disagreement and controversies (doubting whether there was any collective belief characteristic in this group of physicists), but she even shakes up the very idea of individual beliefs. Each scientist (Heisenberg, Bohr, etc.) could be seen as divided into several selves. This paper contends that these two conceptions open important new horizons in several domains, especially if they are linked together. The paper assesses this claim in the light of empirical examples like the Vienna Circle, Copenhagen School, and, eventually, Cartesian philosophy. Key Words: plural subject • polyphony • collective briefs • Cartesian argumentation. (shrink)

This discussion reviews the thinking of some prominent philosophers of argument to extract principles common to their thinking. It shows that a growing concern with dialogical pragmatics is better appreciated as a part of applied ethics than of applied epistemology. The discussion concludes by indicating a possible consequence for philosophy of argument and invites further discussion by asking whether argumentation philosophy has an implicit, underlying moral, or even political, posture.

According to Douglas Walton, the concept of presumption relates to both logical and dialogical components. Logically, a presumption is the conclusion of a presumptive defeasible inference. Dialogically, the function of a presumptions to shift the burden of proof to the respondent in order to move the dialogue forward when the proponent, due to an objective lack of evidence, cannot present a sufficiently persuasive proposition. Presumptive status, assigned only at the argumentation stage of dialogue, is provisional: a particular presumption stands until (...) further counter-indications are found. This paper points out some possible difficulties pertaining to Walton’s dialogical model of presumption. Firstly, once a presumption's typical practical function is made precise, Walton’s idea of presumption starts to lose its conceptual cohesion, thereby becoming applicable in the opening stage of dialogue, as well. Secondly, cohesion is lost also in practical contexts, since Walton's "seat belts" example might indicate that presumptions are not evidentially defeasible if the practical stakes are raised high enough. Most importantly, contextual evaluation may reveal that presumptions do not shift the burden of proof in any specific or genuine way. (shrink)

The paper's thesis is that dialogue is not an adequate model for all types of argument. The position of Walton is taken as the contrary view. The paper provides a set of descriptions of dialogues in which arguments feature in the order of the increasing complexity of the argument presentation at each turn of the dialogue, and argues that when arguments of great complexity are traded, the exchanges between arguers are turns of a dialogue only in an extended or metaphorical (...) sense. It argues that many of the properties of engaged back-and-forth exchanges of paradigmatic argument dialogues are not found in ‘solo’ arguments, and that at least some of the norms appropriate to the former type of argument, such as some of the pragma-dialectical rules of van Eemeren and Grootendorst's model, do not apply to the latter. (shrink)

Do not define argument by its use to persuade. for other uses of arguments exist. An argument is a proposition and a reason for it. and argumentation is an interchange involving two or more parties resulting in the assertion of one or more arguments coupled with anticipated or actual critical responses. A logically good argument has grounds adeq uate for the purposes at hand (true, probable, plausible, acceptable to the audience) and the grounds provide adequate support for the conclusion. The (...) norms for good logic in arguments are different from the norms for the good use of arguments. (shrink)

What role, if any, does dialectic play in Aristotle’s epistemology in the Topics? In this paper I argue that it does play a role, but a role that is independent of endoxa. In the first section, I sketch the case for thinking that dialectic plays a distinctively epistemological role—not just a methodological role, or a merely instrumental role in getting episteme. In the second section, I consider three ways it could play that role, on two of which endoxa play at (...) least a co-starring role. But in the third section, I argue that endoxa don’t play that co-starring role, by arguing for a deflationary account of what endoxa are. For that reason, the third view emerges as the most plausible; but the third view is, I’ll suggest, Platonic. (shrink)

Appeal to expert judgement has become a wide-spread and unavoidable element in public debates in modern society. The many and fundamental argumentative complications that they raise have not received proportional attention in argumentation studies so far. A prominent exception is a recent book by Douglas Walton, devoted entirely to arguments involving expert opinion (Walton, 1997). Confronting some examples from the field of Science and Society with Walton's earlier work, the need can be traced for a more elaborate and sophisticated treatment (...) of the many issues involved, particularly for the model of information seeking dialogue and the treatment of source reasoning. With these issues as points of reference, it is examined in what way this challenge has been taken up in the new book. A few further additions are suggested. (shrink)

In this article, we describe the notion of dialogue move intended as the minimal unit for the analysis of dialogues. We propose an approach to discourse analysis based on the pragmatic idea that the joint dialogical intentions are also co-constructed through the individual moves and the higher-order communicative intentions that the interlocutors pursue. In this view, our goal is to bring to light the pragmatic structure of a dialogue as a complex net of dialogical goals, which represent the communicative purposes (...) that the interlocutors intend to achieve through their utterances. Dialogue moves are shown to represent the necessary interpretive link between the general description of the dialogical context or type and the syntactical analysis of the sentences expressed by the individual utterances. In the concluding part of this article, we show how this method can be used and further developed for analyzing various types of real-life dialogues, outlining possible uses and lines of empirical research based thereon. (shrink)

This paper develops concepts and procedures for the evaluation of complex debates. They provide means for answering such questions as whether a thesis has to be considered as proven or disproven in a debate or who carries a burden of proof. While being based on classical logic, this framework represents an (argument-based) approach to non-monotonic, or defeasible reasoning. Debates are analysed as dialectical structures, i.e. argumentation systems with an attack- as well as a support-relationship. The recursive status assignment over the (...) arguments is conditionalised on proponents in a debate. The problem of multiple status assignments arising on circular structures is solved by showing that uniqueness can be guaranteed qua reconstruction of a debate. The notion of burden of proof as well as other discursive aims rational proponents pursue in a debate is defined within the framework. (shrink)

In this paper we describe a method for the specification of computationalmodels of argument using dialogue games. The method, which consists ofsupplying a set of semantic definitions for the performatives making upthe game, together with a state transition diagram, is described in full.Its use is illustrated by some examples of varying complexity, includingtwo complete specifications of particular dialogue games, Mackenzie's DC,and the authors' own TDG. The latter is also illustrated by a fully workedexample illustrating all the features of the game.

This paper aims at comparing and relating belief revision and argumentation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reasoning they are suitable to deal with. The intended contribution is on one hand assessing the (not fully explored yet) relationships between two lively research fields in the broad area of defeasible reasoning and (...) on the other hand pointing out open issues and potential directions for future research. (shrink)

Doug Walton, who died in January 2020, was a prolific author whose work in informal logic and argumentation had a profound influence on Artificial Intelligence, including Artificial Intelligence and Law. He was also very interested in interdisciplinary work, and a frequent and generous collaborator. In this paper seven leading researchers in AI and Law, all past programme chairs of the International Conference on AI and Law who have worked with him, describe his influence on their work.

In this paper we consider persuasion in the context of practical reasoning, and discuss the problems associated with construing reasoning about actions in a manner similar to reasoning about beliefs. We propose a perspective on practical reasoning as presumptive justification of a course of action, along with critical questions of this justification, building on the account of Walton. From this perspective, we articulate an interaction protocol, which we call PARMA, for dialogues over proposed actions based on this theory. We outline (...) an axiomatic semantics for the PARMA Protocol, and discuss two implementations which use this protocol to mediate a discussion between humans. We then show how our proposal can be made computational within the framework of agents based on the Belief-Desire-Intention model, and illustrate this proposal with an example debate within a multi agent system. (shrink)

We developed an on-line intelligent argumentation system which facilitates stakeholders in exchanging dialogues. It provides decision support by capturing stakeholders’ rationale through arguments. As part of the argumentation process, stakeholders tend to both polarise their opinions and form polarisation groups. The challenging issue of assessing argumentation polarisation had not been addressed in argumentation systems until recently. Arvapally, Liu, and Jiang [, ‘Identification of Faction Groups and Leaders in Web-Based Intelligent Argumentation System for Collaborative Decision Support’, in Proceedings of International Conference (...) on Collaborative Technologies and Systems] earlier developed a method to identify polarisation groups. These groups, however, tend to overlap to a certain degree; each stakeholder may be a member of multiple polarisation groups to varied degrees. Quantifying stakeholders’ membership in multiple polarisation groups is an important issue in the argumentation for collaborative decision-making, which is not addressed earlier. We present a novel approach using fuzzy clustering algorithm to address this issue in this article. The method is evaluated using data sets produced from the discussions of 24 stakeholders. Experimental results indicate that our method is effective for both identifying polarisation groups and quantifying stakeholders’ degree of membership in each polarisation group. (shrink)

During a dialogue, agents exchange information with each other and need thus to deal with incoming information. For that purpose, they should be able to reason effectively about trustworthiness of information sources. This paper proposes an argument-based system that allows an agent to reason about its own beliefs and information received from other sources. An agent's beliefs are of two kinds: beliefs about the environment and beliefs about trusting sources . Six basic forms of trust are discussed in the paper (...) including the most common one on sincerity. Starting with a base which contains such information, the system builds two types of arguments: arguments in favour of trusting a given source of information and arguments in favour of believing statements which may be received from other agents. We discuss how the different arguments interact and how an agent may decide to trust another source and thus to accept information coming from that source... (shrink)